Considering a general washing method using a drum type washing machine, in a state wherein laundry, wash water and detergent(s) are put into a drum of the washing machine, the drum is rotated by a drive force of a motor, causing the laundry to be washed using a frictional force between the laundry and the rotating drum. The drum washing method has less damage to laundry and prevents entangling of laundry while achieving laundry pounding and rubbing washing effects.
Conventional drum washing machines are classified on the basis of a driving method thereof, into an indirect-connection type in which a drive force of a motor is indirectly transmitted to a drum via belts wound on a motor pulley and a drum pulley, and a direct-connection type in which a rotor of a brushless DC (BLDC) motor is directly connected to a drum to directly transmit a drive force of the motor to the drum.
Here, the former indirect-connection type drum washing machine, in which the drive force of the motor is indirectly transmitted via the belts wound on the motor pulley and the drum pulley rather than being directly transmitted to the drum, inevitably suffers from the loss of energy and causes excessive noises.
To solve the problems of the conventional indirect connection type drum washing machine, recently, the use of a direct-connection type drum washing machine using a BLDC motor is expanding.
Now, the configuration of a conventional direct-connection type drum washing machine will be described in brief with reference to FIG. 1.
FIG. 1 is a longitudinal sectional view illustrating the configuration of a conventional drum washing machine. The conventional drum washing machine comprises a tub 2 installed in a cabinet 1, and a drum 3 rotatably installed in the center of the tub 2.
A motor is mounted to a rear wall of the tub 2. The motor includes a stator 6 fixed to an outer surface of the rear wall of the tub 2, and a rotor 5 configured to surround the stator 6, the rotor 5 being penetrated through the tub 2 to be axially connected to the drum 3.
Although not shown, a metallic tub supporter is interposed between the rear wall of the tub 2 and the stator 6. The tub supporter has approximately the same shape as the outer contour of the rear wall of the tub 2. The tub supporter is fixed to the rear wall of the tub 2 in the course of coupling the stator 6 to the rear wall of the tub 2, and serves not only to support the load of the stator 6, but also to maintain the concentricity of the stator 6. The tub supporter is generally fabricated by pressing a steel plate and configured to cover the majority of the rear wall of the tub 2.
A door 21 is installed at a front side of the cabinet 1, and a gasket 22 is installed between the door 21 and the tub 2.
A hanging spring 23 is installed between an inner ceiling surface of the cabinet 1 and an outer top surface of the tub 2, to support the tub 2. Also, a friction damper 24 is installed between an inner bottom surface of the cabinet 1 and an outer lower surface of the tub 2, to alleviate vibrations of the tub 2 caused during a dehydrating operation.
FIG. 2 is a perspective view illustrating the outer appearance of the stator shown in FIG. 1, and FIG. 3 is a perspective view illustrating a dividable core DC included in the stator of FIG. 2. The conventional stator core consists of a plurality of unit cores each being fabricated by pressing a metal plate. The unit core includes a base 150, teeth 151 protruding from one side of the base 150, and a protrusion 500 protruding from the other side of the base 150 opposite to the teeth 151, the protrusion 500 having a coupling bore 500a. The plurality of unit cores are stacked one above another to form a unit core assembly, and then, a plurality of unit core assemblies are circumferentially connected with one another, to complete a so-called dividable stator core.
Here, the coupling bore 500a of the protrusion 500 is required to couple the stator 6 to the rear wall of the tub 2 by means of a bolt, and the protrusion 500 serves to support a fastening load of the bolt penetrated through the coupling bore 500a. 
However, the conventional stator 6 using the above described dividable core DC suffers from a complicated fabrication process as well as a great loss of materials. Further, the weight of the stator increases as much as the protrusion 500.
To fix the conventional stator 6 to the rear wall of the tub 2, the metallic tub supporter should have been essentially provided between the stator 6 and the rear wall of the tub 2. That is, in order to increase the coupling strength of the heavy stator and the rear wall of the tub, the tub supporter having approximately the same shape as that of the rear wall of the tub should have been essentially provided.
Further, there is a great difficulty in the fabrication of the tub supporter having approximately the same shape as that of the rear wall of the tub, and coupling of the tub supporter with respect to the rear wall of the tub tends to increase the number of fabrication processes. This is because the tub supporter, which is made of a steel plate to cover the majority of the rear wall of the tub, is very heavy. However, it is very difficult to couple the heavy tub supporter to the rear wall of the tub for the purpose of maintaining the concentricity of the stator.
For this reason, the above described conventional direct-connection type drum washing machine has a need for reducing the weight of the stator 6 while assuring the stator 6 to be more easily and firmly coupled to the tub 2.